Micrometric plug gauge



April 6, 192e.

G. PONCET MICROMETRIC PLUG GAUGE.

Patented Apr. 6, 1926,

, waan Parana erstes.

GUSTAVE PONCERQF CHICAGO, 111.1111.INOIS.y

Micnolvm'rn'lo PLUG GAUGE.

Application filedy October 2, 1919. SeriaLNo. 327,970.

To all whom t may concern:

Be it known that I, GUsTAvn PONCET, a citizen of Switzerland, residing at Chicago, in the county of Cook and State of Illinois, United States of America, have invented certain new and useful Improvements in Micrometric Plug Gauges, of which the following is a specification.

My invention relates to plug gauges of that type in which the external diameter of the plug may be adjusted to fit within certain prescribed limits, holes orv apertures of varying diameter, the adjustment being effected micrometrically.

The principal objects of the invention are to provid-e a plug gauge of the c lass described, having means' for changing the diameter thereof in such afmanner that the change in the diameter .is readily ascertained; to provide a variable plug gauge of -Y the micrometer type, capable of being used 5o.. three jaws or slidingpart-s 12, mounted in in substantially the same mann-er as an ordinary" micrometer; to provide improved means for locking the gauge in any position or desired adjustment; to provide a gauge `of the class described which may be manufactured accurately and in standard dimen sions by approvedshop practice and machinery; to provide a plug gauge of the class is a side elevation of said gauge; Fig, 2 is an end elevation Vof said gauge shown in Fig. 1; Fig. 3 is a section taken on the line 3-'3 of Fig. 2; Fig. 4 is a section taken on the line 4--4 of Fig. 3; and Fig. 5 lis a section on the line 5-5 of Fig. 3. l

Referring to the drawings, 10 represents a cylindrical plug or body of steel, having a reduced reare'xtension 11, which takes the form of a sleeve, the hole in which sleeve is extended thru the body 10. The body 10 of the gauge serves asa guide for a set of inclined grooves or slots formed in the exterior of the body 10.

As shownbest in Figs. 2 and 4, the said jaws 12 are dove-tailed to fitsnugly in similarly formed body slots, the ioors of the A slots acting as inclined tracks or cams which,

when the jaws are moved along saidslots,

the radius of curvature ofthe body, so that i the jaws will always have co-ntact at the median lin-es of their curved surface, regardless of the diameter of the hole in which the plug gauge is being used.

It will be understood that the plug gauges constructed according to my invention are made in various sizes, for instance inch and a half, inch and three-quarters, two inches, two and one-quarter inches, and etc., each gauge serving for all diameters between its own minimum diameter and the minimum diameter of the next larger size.

Means are provided for effecting .accurately, eliciently, and uniformly, corresponding'action of the jaws. Such means comprises a m-ember for simultaneously moving all of the jaws longitudinally of the body, it being understood that the jaws and 'slots containing them are all uniform in slope, so that va given longitudinal move- 4ment of each jaw will cause a prescribed and uniform movement radially of each jaw of the set.

Hence, it is merely necessary to note the taper` or degree of slope of the slots with reference to the axis of the body and the amount of movement o-f the jaws longitudinally of the axis, to measure the increase inl diameter 'caused by such longitudinall by the power applied thereto and is capable of sliding in the slot 16 when the jaw moves to orv from the axis of the body. l

' It will be observed that the bottoms of the inclined jaw guidewa-ys are'slotted as shown at 15a inFig. 3, in order to permit longitudinal movement ot the arms 15, while at the same time preventing said arms trom rotating.

The position ot the spider ,ll is controlled and determined by the hollow plunger 17. contained within the sleeve lil and having its outer end threaded to lit correspomling threads 1S, termed in the interior ot' the end of the said sleeve or extension l1. The outer end o'l' the plunger or tube 1T a rigid driving tit in the end 1t) ot a micrometer barrel Q0, which. is bored out to rotate and slide upon thel outer circumference ot' the sleeve extension 11.

As shown in Fig. l` the inner end ot the barrel 2O is gradm'ited circ1nnterentially as shown at 21, in addition to which the outer surface ot the sleeve ll is longitudinally graduated as shown at Such graduations enable the amount ot movement ot the jaws to Abe readily ascertained. it being understood the graduation markings are preferably arranged to correspond with the actual diameter tor which the jaws ai'e adj usted.

ln order to enable the jaws to be. moved in either dir Iftion along` the axis of the body, I provide an inner pull-rod or stem 223, extending through the central aperture in the spider 14, having an enlargement or head 24 at its inner end, said head engaging against the outer surface ot the spider 14.

The handle end of the pull-rod 23 is threaded as shown at 25 to tit a correspondingly threaded aperture in the center ot the locking handle 26.y which takes the form of a l-:nurled part, the inner end of which is engaged to abut against the outer end ot the barrel 19.

It will be understood that when locking handle 26 is properly adjusted on the threaded erd 25 of the pull rod 23, the spider 11i may be made to litl without shake or movement between the head .24 and the end et' the plunger 17.

Then changing the diaieter or adjusting the gauge, it is obviously necessary to permit rotary movement ot the parts .17 and Q-l with reference to the spider 14, which is relatively stationary, so far as rotary movement is concerned. It is also desirable to have the tool set so as to permit such relative rotary movement to allow of the adjustment of the device,l while at the same time elin'iinating inaccuracy due t-o an excessive looseness of the parts.

Hence, I tind it advisable in practise to set the .locking piece QG on the threaded en( of the pull rod in the required posi- Ytion ot adjustment and then provide means for preventing the parts from accidentally losing said adjustment; said safety means comprises a small `ball 27 which is kforced into the small recess 28 in the tace of the barrel-end 19 by means of a coiled compression spring '29, contained in an aperture 30, drilled longitudimilly in the lock-piece QG. The outer end ot' said aperture Btl is closed by a screw plug ill. said end heilig slightly reduced in diameter so as to prevent thr` vball 2T trom becoming lost.

lt should be stated that in order to prevent the rod 23 Vtrom turning in the plunger l?. when the lock' piece 2G is turned for adjustment. the outer end ot' the plunger 1,7 is extended into the inner end ot the lock-piece 2G and is slotted as shown at to accommodate a transverse diametric pin in the pull-rod 2?).

ln using my improved plug gauge. l [ind it desirable in certain instances to be abie to lock the jaws ot the device against movement alter they have been set to some particular or desired diameter. Such locking is readily effected by tightening up the lockpiece 2li so as to clamp the spider 'll tightly between the end ot the plunger 1T and the shoulder ot the pull rod head .lt will be understood that. the ball QT does not'. absolutely preventmovement ot the lock piece 2U, which can still be rotated in order to ette-ct such clan'iping action.

It will be manifest to those skilled in the art that my improved device is capable ol' a wide variety of ditferent uses and applications in the tool-room, and effect-s a marked economy especially when compared with the former practise of preparing special plug gauges for each particular job involving a slightly differentdiameter or aperture.

The device is also et great utility as a n'iicron'ieter Jfor measuring the diameter of a hole or aperture which is being worked on. and also ot service as a rigid plug gauge tor insertion in an aperture, the distance of which from some other point or part is to be ascertained.

Although I have described my inv it-ion in considerable detail, it will he understood that the scope ot the invention is not limited by the description ot said details` but should be determined bv reterence to the appended claims, said claims being construed as broadly as possible, consistent with the state ot the art.

I claim- 1. A .plug gauge comprising a cylindrical body provided with a sleeve extension coaxial with the said body, said body being formed with a series of symmetrically disposed guideways inclined at an angle to the. axis ot the body` jaws slidably fitting in corresponding guidewaysi a centrally disposed radially extending non-rotary member having means engaging said jaws 'tor moving the same longitudinally, a plunger contained within said sleeve extension threaded therein and having an end engaging said member, a rod contained within said plunger and havsaid Slt)

ing an ei'ilargement for engaging the opposite side of said member, and means for forcing said enlargement towards said plunger to lock said plunger against rotary movelent in said sleeve.

2. A plug gauge comprising a cylindrical body provided. with a sleeve extension coaxial with the said body, said body being formed with a series of symmetrically disposed guideways inclined at an angle to the axis of the body, jaws slidably iitting in corresponding guideways, a centrally disposed radially extending non-rotary member having means engaging said jaws for moving the same longitudinally, a plunger contained within said sleeve extension threaded therein and having an end engaging said member, a rod contained within said plunger and having an enlargement for engaging the opposite side of said member, and means for forcing said enlargement towards said plunger to lock said plunger against rotary movement in said sleeve, said means comprising a lock-piece carried by said plunger and having threaded engagement with said rod.

3. .A plug gauge comprising a body portion provided with a threaded axial bore and an inclined guideway, a jaw slidable in said guideway, a threaded member fitting within the bore oit said body portion and movable longitudinally therein by the relative rotation of said body portion and said member for effecting movement of said jaw in said gnideway, and an operating handle fitting over one end of said body portion and connected to said member.

4f.. A plug gauge comprising a body p0rtion provided with a threaded axial bore and an inclined guideway, a jaw slidable in said guideway; a threaded member fitting Within the bore of said body portion and movable longitudinally therein by the relative rotation of said body portion and said member for effecting movement of said jaw in said guidevvay, an operating handle fitting over one end of said body portion and connected to said member, and means for locking said member Within said bore.

GUSTAVE PONCET. 

